LU-18813 osd-wbcfs: refactor osd_device_alloc

LU-18813 osd-wbcfs: refactor osd_device_alloc

osd_device_alloc() has improper error handling.
Refactor the function such that we properly
cleanup if __osd_device_init() fails.

Test-Parameters: trivial
Test-Parameters: testlist=sanity fstype=wbcfs mdscount=4 mdtcount=1 osscount=4 ostcount=1
Test-Parameters: testlist=sanity fstype=wbcfs combinedmdsmgs=false standalonemgs=true mdscount=1 mdtcount=1 osscount=4 ostcount=1
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: Ia03eb805ef3fdc75c8490e09c66b99e6541d13fd
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/59306
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Qian Yingjin <qian@ddn.com>
Reviewed-by: Lijing Chen <lijinc@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>